Mendilibar replaces Camacho at Osasuna
The 49-year-old Mendilibar, former coach of Athletic Bilbao and Valladolid, has agreed a contract until the end of next season and will be presented at a news conference on Tuesday, the club said on their website.
He helped Valladolid back into the top flight as second division champions in 2007 and led them to 15th and 16th-placed finishes before being sacked last February.
Osasuna president Pachi Izco told a news conference it had been a difficult decision to get rid of Camacho, a former Spain coach, but one that had been taken at the right time despite the home win over Real Madrid at the end of last month.
"The recent run of results has not been good and in football the results are what count," Izco said.
"We are in the relegation zone and the image of the club, except on the day of the Real Madrid game, has not been good."